According to fire protection codes, when should fire dampers be used?

Fire dampers are essential components in HVAC systems designed to prevent the spread of fire and smoke through ductwork. They are specifically required in air ducts that pass through fire-rated walls or partitions, such as those found in light commercial installations. The primary function of a fire damper is to automatically close when it detects heat, creating a barrier that slows or stops the movement of flames and smoke.

In the context of the other options, commercial kitchens often require grease ducts and specialized extinguishing systems but do not universally necessitate fire dampers in their air distribution systems. Ducts located outside buildings may not need fire dampers due to reduced risk of fire spread in external environments. Lastly, while fire dampers are crucial, they are not mandated in all duct systems irrespective of their type or installation context. Each fire protection requirement is specific to the potential risks posed by the environment in which the ducts are located. Hence, the requirement for fire dampers is limited to areas where they can effectively reduce the risk of fire and smoke transmission, which is why their installation in ducts passing through fire-rated boundaries is vital.